Error 7312 During Shape Optimization

Altair Forum User

Hi Everyone,

 

I'm trying to fine-tune a topology optimized part using free shape optimization on some of the members. Unfortunately when I run Optistruct, it gives me the following:

 

*** ERROR # 7312 ***
  DSHAPE card    1 contains    2 disconnected patches. Patch(es) listed
  below contain too few grids that are likely insufficient for defining a smooth
  surface/curve.

 

I can't find anything on this error. Also, it doesn't list any 'patches' so I'm not even sure where it's having problems. Any advice?

 

Thanks!

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tinh

Maybe you selected too few nodes or nodes are not adjacent , select more adjacent nodes again

Altair Forum User

Thanks for your help! I think the issue was that near where the members meet the mesh strays slightly from the geometry to prevent really thin tetra elements and thus when I use select nodes by geom some nodes don't get selected and so there are patches of unselected nodes within the selected regions. I had been making a desvar for each member I wanted changed but considering my settings for all of them were the same I remade a single desvar containing all of the regions and the solver got past the point where the previous error was. However, now it is giving me:

 

*** ERROR # 1814 ***

VOLFRAC response on DRESP1 card 3 is not applied to a topology or free-size domain.

 

I'm doing a minimize volfrac objective with a stress constraint. Is this not allowed for a free-shape optimization?

 

Thanks!

Altair Forum User

Ok yeah now I realize my mistake. Volfrac doesn't exist for shape optimization because that doesn't make sense. I'll do a minimize volume objective.